(1) Technical Field
This invention relates to devices for insufflating gas into a mass of molten metal.
(2) Description of the Prior Art
Prior structures of this type have generally employed permeable plugs through which the gas is introduced into the liquid. Such typical devices may be seen in U.S. Pat. Nos. 2,811,346, 2,947,527, 3,330,645, 3,610,602 and 3,343,829.
U.S. Pat. No. 3,343,829 discloses a plug having an outer non-permeable shell and an inner gas permeable portion. The present invention avoids the problems that have been commonly associated with the prior art devices and particularly the blocking and delaying of the introduction of the gas flow by the first contact of the device with molten metal or slag poured into the ladle.